It appears that Gríma Wormtongue does indeed have business in Madh-fushaum, and his journey this far north was no coincidence. He may yet have a role to play in the struggle in the Stonedeans.
You find Gríma Wormtongue in a heated discussion with the leaders of Madh-fushaum. It is pretty clear he is unhappy about something, and you should see what he has to say....
You once again encounter Gríma Wormtongue, this time reprimanding the leaders of Madh-fushaum for what appear to be failures on their part. He clearly had business to attend to here before departing for Isengard.
You should observe Gríma reprimanding the leaders of Madh-fushaum for what appears to be failures on their part. You may be able to learn what involvement he has in the situation in the Stonedeans.
Gríma has finished his business in Madh-fushaum and now departs for Isengard.
What you observed of Gríma Wormtongue's business with the leaders of Madh-fushaum and the role he has played in the Stonedean's turmoil would be wise to share with Herubrand.